1. Field of the Invention
The present invention is directed to air conditioning systems, and more specifically, to a blowerless air conditioning or heat pump system.
2. Background Information
Many homes, especially mobile or manufactured homes, include a forced hot air furnace for heating the home. A common type of forced hot air furnace is a down-flow furnace, in which a burner generates hot combustion gases and forces them to flow upwardly through a heat exchanger. A blower is typically disposed above the heat exchanger to draw room air into the furnace and force it downwardly past the heat exchanger. As this room air flows past the heat exchanger, it is heated. This heated air typically exits at the bottom of the furnace which is coupled to a series of ducts extending from the furnace to the various rooms of the home. The blower is powerful enough to drive air not only past the heat exchanger, but also through these ducts and into the rooms being heated.
Another common type of furnace is an electric furnace. A blower is typically disposed above one or more electric heat elements within the furnace. The blower draws room air into the furnace and forces it downwardly past the elements. As in the fossil fuel furnace, the air is heated and the blower is powerful enough to drive the air through the ducts to the various rooms of the home.
It is often desirable to add air conditioning to these homes, usually at the time the home is installed. Most air conditioners have two main components: an evaporator coil which is installed with the furnace, and a condensing unit which is located outside of the home. The evaporator coil and condensing unit are connected together by a pair of copper pipes in which the system""s refrigerant flows. The condensing unit typically includes a compressor or pump, a condenser coil and an outdoor fan and motor combination. The evaporator coil is typically connected to the home""s air distribution ducts that lead to the various rooms being conditioned. When cooling is desired, liquid refrigerant is pumped through to the evaporator coil where it evaporates absorbing heat from the air being blown over the evaporator coil by the fan and motor in the furnace. This cooled air is then forced through the ducts and into the rooms. Evaporated refrigerant flows to the compressor where it is compressed. Hot, high pressure gas exiting the compressor is then pumped through the condenser coil where it is cooled by the air being forced through the condenser coil by the outdoor fan, causing the refrigerant to condense back into a liquid. The liquid then flows to the evaporator coil through an expansion device which dramatically lowers its pressure. The refrigerant is now very cold and flows through the evaporator coil completing the cycle.
The air conditioning system may also be formed as a single package unit containing both the evaporator coil and the condensing unit. A package air conditioning system also includes a blower and duct connections which are tied to the home""s duct system. This type of package system is typically mounted outdoors and is used in conjunction with a damper which prevents the cooled air generated by the system from entering the furnace already installed in the home.
U.S. Pat. No. 5,740,790 describes a typical type of air conditioning system, which is made as an add-on to the down-flow furnace described above. Here, the furnace is raised and an enclosure is mounted underneath the furnace between the heat exchanger and the feeder duct which leads to the home""s air distribution ducting system. Disposed in this new enclosure is the evaporator coil of the air conditioner. To provide air conditioning, the furnace""s blower is activated, but not its burner. The blower forces air past the evaporator coil in the enclosure and into the air distribution duct system. Pressurized liquid refrigerant is supplied to the evaporator coil from a condensing unit. The refrigerant evaporates within the evaporator coil extracting heat from the air. This cooled air then flows through the air distribution duct system and into the rooms of the home.
In electric furnace systems, the air conditioning evaporator coil is typically added on top of the furnace. As in the fossil fuel furnace, the blower runs with the electric heat elements off to force room air to be cooled through the evaporator coil.
Although quite popular, air conditioning systems, such as those described above, especially the combined or split systems, can be relatively expensive due to the number of required components and difficult to install. Accordingly, many individuals wishing to obtain air conditioning for their homes simply cannot afford the costs of the system.
The system described in the U.S. Pat. No. 5,740,790 has several disadvantages. For example, it requires the existing furnace to be raised, requiring additional space within the home in order for the enclosure to be installed. For many furnace installations, it is not possible to raise the furnace due to its location in the home, thereby precluding this type of air conditioner. The air conditioning unit must also be designed with the particular furnace in mind since it mounts directly to the furnace. In addition, due to the location of the evaporator coil, condensate forming on the coil may enter the home or heating system causing water damage.
Also, a set of copper tubes, must be run from the evaporator coil to the condensing unit. These tubes are susceptible to leaks and damage which generally cause the air conditioning unit to fail, and which may also result in environmental damage.
The package system described above also has several disadvantages. The system requires a damper to be installed underneath the existing furnace. Further, the home now has two blowers (one in the furnace and one in the package unit), which adds cost to the overall system.
It is an object of the present invention to provide an economical air conditioning or heat pump system that can be installed regardless of the type of forced hot air furnace being used.
It is a further object of the present invention to reduce labor costs involved in the installation of an air conditioning system.
It is a still further object of the present invention, to reduce the number of components required by the air conditioning system.
Briefly, the invention relates to a blowerless air conditioning or heat pump system for providing conditioned (e.g., heated, cooled and/or dehumidified) air. The system includes an outdoor section that is joined to an indoor section, and is advantageously used with a preexisting air moving system, such as a forced hot air furnace, and a corresponding air distribution duct system. The two sections are preferably installed along a boundary of the space being cooled (e.g., along a skirt or exterior wall of a home) such that the outdoor section is outside of the home and the indoor section is inside or below the home and proximate to a forced hot air furnace. Disposed within the outdoor section are a compressor, an outdoor coil and an outdoor fan. Disposed within the indoor section is an evaporator coil. In accordance with the invention, there is no separate fan or blower disposed within the indoor section. The system further includes an inlet air conduit that couples the indoor section to a first point in the air distribution system, and an outlet air conduit that couples the indoor section to a second point in the air distribution system. The second point is downstream of the first point relative to the furnace. The system may also include a dam that is positioned between the two points in the air distribution system.
In operation, the compressor compresses a refrigerant and pumps it to the outdoor coil within the outdoor section where it is cooled and liquefied. Liquid refrigerant flows through an expansion device substantially lowering its pressure and enters the evaporator coil within the indoor section. The blower (but not the burner or electric heating elements) within the furnace is also activated, thereby forcing air through the furnace and into the air distribution system. By virtue of the dam, the air is diverted through the inlet conduit, into the indoor section and through the evaporator coil. As refrigerant flows through the evaporator coil, it evaporates, thereby absorbing heat and/or humidity from the air flowing into the indoor section. This xe2x80x9cconditionedxe2x80x9d air is then returned to air distribution duct system by the outlet conduit, where it can be distributed throughout the home. The refrigerant from the evaporator coil, is conveyed to the compressor thereby completing the cycle. This process is repeated as long as conditioned air is being requested within the home.